The present disclosure relates generally heating, ventilating, or air conditioning (HVAC) systems and more particularly to predicting equipment failure in a HVAC system.
HVAC actuators are used to operate a wide variety of HVAC components such as air dampers, fluid valves, air handling units, and other components that are typically used in HVAC systems. For example, an actuator can be coupled to a damper, valve, or other movable equipment in a HVAC system and can be used to drive the equipment between an open position and a closed position. An actuator typically includes a motor and a drive device (e.g., a hub, a drive train, etc.) that is driven by the motor and coupled to the HVAC component.
Equipment failure may occur when the actuator is unable to move the equipment, which can result in the equipment becoming stuck (e.g., stuck open, stuck closed, or stuck an intermediate position). Equipment failure can be caused by increased frictional wear and/or degradation of linkages and equipment components over time. Such wear and degradation can be accelerated by corrosive salt air if the equipment is installed in a marine environment.
Some actuators are configured to compensate for increased friction (i.e., increased resistance to movement) by increasing the electric current provided to the motor. Increasing the electric current provided to the motor causes the motor to apply an increased torque to the drive device and the equipment. Such compensation can be effective until the torque required to move the equipment exceeds a torque limit, at which point the motor stalls and the equipment becomes stuck.
Conventional actuators typically only output a feedback signal indicating the actuator position, but do not output or report any other types of data. Accordingly, equipment failure typically occurs with no warning, resulting in a time period of ineffective equipment operation until the equipment is repaired or replaced. It would be desirable to predict equipment failure before such failure occurs. However, typical actuators are unable to communicate the operational data required to equipment damper failure.